Process of rendering vitreous compounds turbid.



manufacture and in particular to the method UNITED slams PATENT orr cn.

LUDWIG WEISS, OF MUNICH, GERMANY.

PROCESS OF RENDERING VI'lR-EOUS COMPOUNDS TURBID.

No Drawing.

T 0 all whom it may concem:

Be it known that I, LUDWIG lVEIss, chemist, citizen of Germany, residing at Munich, Germany, have invented certain new and useful Improvements in Processes of Rendering Vitreous Compounds Turbid; and I do hereby declare the following to be a full, clear, and exact description of theinvention, such as will enable others skilled in the art to which it appertains to make and use the same.

This invention relates to the art of-glassof rendering vitreous compounds, such as glass, enamel and the like cloudy, semiopaque or turbid.

The object of the said invention is to produce such cloudiness or semi-opacity in a uniform and even manner, such as it has not been possible to effect by the methods hitherto practiced for this purpose.

'Heretofore it has been customary to employ cryolite, fluor-spar, oXid of tin or of zirconium, oXid of titanium, phosphate of calcium or bone-ash, antimonious acid or large quantities of silicic acid or oxid of zinc. These substances render the vitreous mass into which they are introduced, cloudy or murky, by virtue of the fact that they are not dissolved in the melt, or are precipitated in a solid condition. as opaque masses on cooling or reheating of the vitreous compound. In carrying out the old methods it is immaterial whether the glass is rendered opaque in this way or is applied to a metal backing in the form of an enamel. The effect and appearance is the same in both cases. Under the present invention an essentially difierent reaction and effect is attained. In carrying out the same, a compound of boron, preferably boraX or'trioxid of boron, is melted together with the oXid of zirconium. As equivalents of the mid of zirconium, oxids of other diflicultly fusible elements, preferablv the tetravalent elements, such as silicon, tin, tetravalent, lead, titanium, or thorium may be used. If sufficient quantities of the flux or boron compound are employed, the mass will'be fused to a transparent vitreous mass. Under this invention substantially saturated solutions of one or more of these metals in the flux are employed, and the mass after fusion is cooled, steam or acid vapor being concur- Specification of Letters Patent.

rently passed into contact With the mass, that is to say over or through the same. The vitreous mass is thereby rendered turbid. This is due to the fact that under this treat ment a special kind of double compounds of boric acid is formed and precipitated. If the mass is slowly and gradually cooled, or allowed to cool, these double compounds are separated as extremely fine amorphous par- .ticles which are uniformly disseminated throughout the mass. The distribution is the least'perfect in the case of thorium.

I have found that the above complex boron compounds effectually resist the action of acids and generallyof lyes; they are only dlssolved by-hydrofluoric acid and they are therefore admirably adapted for rendering turbid such glasses and vitreous compounds whose use exposes them to the action of acids and lyes. j

In carrying out my invention, I preferably proceed as follows: I melt a quantity of one of the boron compounds above mentioned, such as borax or trioxid of boron, together with one or several of the refractory oXids above mentioned and then, while cooling or allowing the mass to cool, I pass steam or acid vapor over or through the melt, that is, into contact with the same.

The mass so obtained is then added to the vitreous mass, such as glass or enamel, to be renderedturbid. Another way of proceeding is to add the .flux or boron compound together with the refractory oXid to the vitreous mass to be rendered turbid at the beginning and then to proceed as above, that is to say, to subject the same to the action 'of steam or acid vapor which is caused to pass .into contact with the mass while cooling.

The advantages of the new process con- ,sist in the fact that the clouding of the vitreous mass is made extremely uniform and that the agents for producing this result act-much more eflectively, comparatively small quantities of the same being only required. It is also important to note that the clouding eifect produced is always successful under my invention and, moreover, the degree of turbidity or cloudiness of the finished product may be regulated and controlled, with nicety"accordingto the length of time during which the heated vapor, such as steam or acid vapor, is caused Patented Aug. 29, 1911. Application filed June 1, 1909. Serial No. 499,494. I i

to act on the melt, or to the amount of the vapor employed.

Having thus fully described my invention, What I claim is 1. The process of preparing turbid vitreous compounds, which consists in causing a heated vapor to act on a fused mass containing a boron compound and a refractory oxid, and concurrently cooling the mass.

2. The process of making turbid vitreous compounds, which consists in causing a heated vapor to act on a fused mass containing a boron compound and an oxid of a tetravalent element, and concurrently cooling the mass.

'3. The process which consists in cooling a fused vitreous mass containing a boron compound and an oxid ofa tetravalent element, and concurrently passing steam into contact with the same.

cooling and causing a heated vapor to act on a melted mixture of its ingredients.

6. As a new composition of matter a vitreous mass containing finely disseminated particles of a double compound of boron formed with a tetravalent element, which double compound has been formed by coincident-ly coolin and causing a heated vapor to act on a melted mixture of its ingredients.

7 As a new composition of matter, a vitreous mass containing particles of a double compound of boron with zirconium distributed throughout said mass.

8. As a new composition of matter, a double compound of boron and zirconium,

which is not attacked by lyes and acids, with the exception of hydrofluoric acid.

9. As a new composition of matter, a turbid vitreous mass containing particles of a double compound of boron and zirconium, said compound being finely distributed throughout the mass and not attacked by lyes or acids, with the exception of hydrofiuoric acid.

In testimony whereof-I hereunto affix my signature in the presence of two'witnesses.

LUDWIG WEISS.

Witnesses:

ABRAHAM SCHLESINGER, LoUIs MUELLER. 

